1. Field of the Invention
This invention relates to key broach tools for cutting keyways in a workstock and more particularly, to a device for stabilizing a workstock on a broach tool guide sleeve while a key broach tool extending through the guide sleeve cuts a keyslot in the annular bore wall of the workstock, typically by operation of a hydraulic press. In a preferred embodiment the device is characterized by a pair of top and bottom end plates, each provided with a semicircular notch for receiving the cylindrical guide sleeve at opposite ends of the workstock after the workstock is positioned on the guide sleeve. Each end plate includes a bevelled surface for engaging the corresponding open end of the workstock. A bolt is extended through the end plates and the bore of the workstock and nuts are threaded on the opposite ends of the bolt to secure the end plates against the workstock. In typical application of the device the lower end of the guide sleeve with the assembled device is secured between the adjacent support panels or plates of a work table, with the bottom end plate resting on the plates or panels of the work table and the key broach tool is extended downwardly through the slotted guide sleeve and workstock by operation of a hydraulic press. As the key broach tool cuts the key slot in the annular bore wall of the workstock, the end plates on the slotted guide sleeve prevent lateral displacement of the workstock on the guide sleeve and secure the workstock against the cutting edge of the key broach tool. A semicircular keeper can be positioned on the work table engaging the slotted sleeve for stabilizing the key broach tool in the guide sleeve.
To facilitate cutting a keyway linearly in the annular bore wall of a cylindrical workstock such as a hub collar or sleeve, for example, a slotted broach tool guide sleeve or bushing, upon which the workstock is positioned, is typically used to support and guide a key broach tool through the workstock bore as a hydraulic press extends the vertical key broach tool downwardly through the workstock to cut the keyway in the workstock. Standard or conventional broach tool guide sleeves are characterized by an elongated, slotted sleeve having a selected length and diameter and which is secured in a vertical position between the adjacent support panels or plates or a work table or bench and initially receives the cylindrical workstock. A vertical key broach tool is positioned in the longitudinal slot of the secured guide sleeve and a hydraulic press extends the key broach tool downwardly through the guide sleeve and workstock, to cut the key slot in the workstock. Due to the horizontal pressure exerted by the key broach tool against the interior bore wall of the workstock, the workstock has a tendency to become laterally displaced if it is not firmly secured on the guide sleeve. Accordingly, the device of this invention provides a mechanism for stabilizing a workstock on a slotted guide sleeve and against the cutting edge or teeth of a key broach tool extending through the guide sleeve in order to prevent displacement of the workstock on the guide sleeve and facilitate more precise cutting of the key slot in the workstock.
2. Description of the Prior Art
Several devices are known in the art for securing a workstock in a position which facilitates cutting a key slot in the workstock. U.S. Pat. No. 430,133, dated Jun. 17, 1890, to Addison M. Little, describes a "Mandrel For Key Seat Cutting Machines" designed to cut a key slot in the interior hub bore wall of a wheel hub while the wheel rests on a work surface. A key is initially extended downwardly through the wheel hub bore and into the work surface to secure the hub to the work surface. The mandrel reciprocates in the wheel hub adjacent to the key to cut a key slot in the annular bore wall of the hub. A rectangular bar can be inserted in the hub bore between the key and the mandrel, as needed, in order to maintain a tight fit of the mandrel against the hub bore wall. U.S. Pat. No. 722,222, dated Mar. 10, 1903, to John T. Fuhrmann, discloses a "Valve Dressing Tool" for dressing valve seats. The valve seat to be dressed is initially bolted to a mandrel guiding plate, and the valve dressing tool is next extended through the mandrel guiding plate and reciprocated in the secured valve seat to dress the annular interior of the valve seat. A "Device For Cutting Key Seats or the Like" is disclosed in U.S. Pat. No. 870,971, dated Nov. 12, 1907, to Conrad Lindstrom. The Lindstrom device is characterized by a slotted chisel guide sleeve which is clamped against a workstock in which a keyslot is to be chiseled, with the slot of the guide sleeve facing the workstock. A slideway is provided in the other side of the guide sleeve for receiving a tapered key between the clamp and the sleeve, to achieve a selected tight fit of the sleeve against the workstock. A hand chisel is impelled by the strokes of a hammer or mallet in the guide sleeve slot to facilitate cutting a key slot in the workstock. U.S. Pat. No. 4,284,377, dated Aug. 18, 1981, to Bert W. Piper, describes a "Portable Key Seat Cutter" including a shank on which a pulley is adapted to be clamped. A broach tool blade is slidably disposed in a groove provided in the shank and extends through a bore in the pulley. The key seat is cut in the pulley bore by manually pivoting a handle to effect repeated strokes of the broach tool blade. The depth of the cut is progessively increased to the desired depth of the slot between successive strokes of the blade by incremental advancement of a tapered feed bar in the groove on the shank on which the broach tool blade is slidably mounted. A "Keyway Broach Guide Assembly" is detailed in U.S. Pat. No. 5,150,996, dated Sep. 29, 1992, to Glenn R. Thoroughman. The broach guide assembly includes a tapered wedge and a broach tool guide member which is positioned in longitudinally-abutting relationship to the tapered wedge to form a broaching bushing of substantially rectangular cross-section for insertion in the bore of a workstock. The width of the broach guide assembly is adjusted to fit tightly in the workstock bore by longitudinal shifting of the tapered wedge and guide member relative to each other.
An object of this invention is to provide a device for stabilizing a workstock on a slotted broach tool guide sleeve while a key broach tool cuts a key slot in the workstock.
Another object of this invention is to provide a device for stabilizing a cylindrical workstock on a slotted broach tool guide sleeve while a key broach tool cuts a key slot in the annular bore wall of the workstock.
Still another object of this invention is to provide a device for stabilizing a workstock on a slotted broach tool guide sleeve while a key broach tool cuts a key slot in the annular bore wall of the workstock, which device in a preferred embodiment is characterized by a pair of end plates which receive the broach tool guide sleeve and engage respective ends of the cylindrical workstock positioned on the guide sleeve and a bolt which is extended through the end plates and workstock and receives nuts on the ends of the bolt to secure the end plates against the cylindrical workstock and stabilize the workstock against the cutting edge of the key broach tool.
Yet another object of this invention is to provide a device for stabilizing a cylindrical workstock on a broach tool guide sleeve while a key broach tool extending through the guide sleeve cuts a key slot in the annular bore wall of the workstock, which device is characterized by a pair of end plates, each having a sleeve notch for receiving the cylindrical guide sleeve and a bevelled surface for engaging the corresponding end of the cylindrical workstock, and a bolt which is extended through the spaced end plates and the bore of the workstock and receives nuts on the respective ends of the bolt to secure the end plates against the workstock, which end plates prevent lateral displacement of the workstock on the guide sleeve and stabilize the workstock against the cutting edge of the key broach tool as the key broach tool cuts a key slot in the workstock by operation of a hydraulic press.